The present invention relates to implantable medical devices such as cardiac pacemakers and defibrillators. More particularly, the present invention pertains to implantable medical device telemetry control systems and methods for their integration and use with automotive vehicles.
A wide variety of implantable medical devices (IMDs) are known and commercially available. Generally, these devices utilize a bio-compatible case having a connector block mounted thereto. The connector block includes receptacles for leads that may be used for electrical stimulation and/or for sensing physiological activity. For example, an implantable cardiac device, e.g., an implantable pacemaker-cardioverter-defibrillator (PCD), may use such leads to monitor activity of a human heart and to deliver therapy thereto in the event undesirable heart activity is detected. For the sake of brevity, the remainder of this discussion will focus on IMDs for treatment of cardiac conditions. However, it is understood that the present invention is equally applicable to IMDs of most any purpose.
For many cardiac IMD patients, all that is required to maintain regular cardiac function is pacing shocks delivered to a particular area of the heart. These cardiac events and the resulting pacing shocks are generally mild and the patient typically experiences no significant sensation. However, for more serious cardiac conditions, e.g., ventricular fibrillation (VF) and ventricular tachycardia (VT), the patient may experience immediate incapacitation and even loss of consciousness. Further, the therapy delivered in response to such severe cardiac events is often sufficient to cause significant discomfort, further disorienting or incapacitating the patient. Accordingly, IMD patients who suffer from more severe ,cardiac conditions are often restricted from driving a vehicle or from operating other potentially dangerous machinery as the occurrence of a severe cardiac event may endanger their lives and/or the lives of others.
Yet for many cardiac IMD patients, the occurrence and severity of cardiac arrhythmias does not warrant absolute driving restrictions. For example, some PCD patients may never experience a cardiac event at all, let alone during the limited time they may be driving. In fact, at least one study has shown that recipients of implantable cardioverter defibrillators have no more frequent motor vehicle accidents than the general population. See xe2x80x9cModification of Patient Driving Behavior After Implantation of a Cardioverter Defibrillator,xe2x80x9d Conti et al., PACE, Vol. 20, September 1997, pp 2200-2204, 2203. Nonetheless, given even the potential for harm to the patient-driver, passengers, pedestrians, and surrounding vehicles, it is often perceived that driving restrictions for some or all cardiac IMD patients are justified.
The ability to drive, however, is viewed as an important aspect of maintaining one""s independence. Accordingly, a solution short of totally restricting the IMD patient""s driving privileges would be advantageous.
One partial solution is discussed in U.S. Pat. No. 5,332,400 to Alferness, entitled xe2x80x9cAtrial Defibrillator and Method for Providing Pre-Cardioversion Warning,xe2x80x9d issued Jul. 26, 1994. The ""400 patent describes an implantable atrial defibrillator capable of providing warning electrical energy to the patient when the patient""s heart is in need of cardioversion before the delivery of cardioverting electrical energy. The warning electrical energy is of a quantity that is less discomforting than the quantity required to cardiovert the atria. An implantable sensor having a similar warning device is described in U.S. Pat. No. 5,404,877 to Nolan et al., entitled xe2x80x9cLeadless Implantable Sensor Assembly and a Cardiac Emergency Warning Alarm,xe2x80x9d issued Apr. 11, 1995.
While effective, the warning devices described in the ""400 and ""877 patents rely on the judgement of the driver to take immediate precautionary measures, e.g., stop. Further, for patients who suffer a severe cardiac event, e.g., a hemodynamically unstable VT or VF, therapy must typically be delivered immediately. In such situations, the time delay between warning and therapy delivery is not always sufficient to permit the driver to take adequate precautionary measures.
While they do not wam the patient of impending therapy, other devices are known which can monitor implant status and locate the patient based on global positioning system (GPS) coordinates. For instance, see U.S. Pat. No. 5,752,976 to Duffin et al., entitled xe2x80x9cWorld Wide Patient Locator and Data Telemetry System for Implantable Medical Devices,xe2x80x9d issued May 19, 1998. The ""976 patent describes a system for communicating patient device information to and from a medical device implanted in an ambulatory patient and a remote medical support network.
U.S. Pat. No. 5,729,205 to Kwon, entitled xe2x80x9cAutomatic Transmission System of an Emergency Signal and a Method thereof Using a Driver""s Brain Wave,xe2x80x9d issued Mar. 17, 1998, describes a system which enables police and hospitals to provide a proper and immediate rescue operation for those involved in an accident. The system operates by transmitting an emergency signal via GPS. The signal is derived from a particular brain wave generated when the driver is in critical condition.
Accordingly, various implementations of systems for warning a patient of impending cardiac therapy are known as are systems for transmitting IMD status or patient status/location to remote facilities. These systems are described above and in the documents listed in Table I below.
All documents listed in Table 1 herein above are hereby incorporated by reference in their respective entireties. As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of the Embodiments, and claims set forth below, many of the devices and methods disclosed in the documents of Table 1 and others documents incorporated by reference herein may be modified advantageously by using the teachings of the present invention.
The present invention has certain objects. That is, various embodiments of the present invention provide solutions to one or more existing problems with respect to vehicle operation by IMD patients. One such problem involves the need to warn the patient-driver of a detected medical event and the onset of IMD therapy. In many instances, adequate warning permits the patient-driver to direct the vehicle to a safe and stopped position prior to therapy delivery. Another problem for patient-drivers with IMDs concerns more severe medical events, e.g., ventricular tachycardias, that can incapacitate the patient or even lead to loss of consciousness. If such an event occurs during driving, the patient-driver may lose consciousness before reaching a safe and stopped position. Other problems include the need to promptly notify emergency personnel of the medical event and the precise location of the patient-driver.
The IMD control systems and methods of the present invention provide one or more of the following advantages. The IMD is able to transmit an event signal indicative of the occurrence of a medical event, e.g., cardiac arrhythmia, to a vehicle control module associated with the vehicle. The vehicle control module may provide a warning alert to the patient-driver that a medical event has occurred and therapy is required. Where the nature of the medical event permits, the driver may be instructed to stop the vehicle as soon as possible.
Where the medical event is more serious, the vehicle control module may command the vehicle to slow or stop with little or even no input from the patient-driver. This is achieved via a command signal generated by the vehicle control module. In one embodiment, the command signal is transmitted to the vehicle ignition system, commanding the vehicle engine to slow or stop. In another embodiment, the command signal is provided to the brake system commanding the brake system to stop the vehicle. These command signals may be capable of completely stopping the vehicle without reliance on input from the patient-driver. Accordingly, telemetry control systems and methods according to the present invention are advantageous in that they permit assisted vehicle control in the event an IMD patient-driver experiences a medical event during vehicle operation.
The vehicle control system may also operate with a communication module such as a cellular telephone system. Upon the occurrence of a medical event, the vehicle control system may initiate an automated emergency call, alerting local emergency personnel to the medical event. A GPS module may, in conjunction with the communication module, provide the location of the vehicle, expediting arrival of emergency personnel. Other embodiments of the present invention may activate and/or control other vehicle subsystems. For instance, external emergency signals may be activated to notify other drivers.
Some embodiments of the present invention include one or more of the following features: an IMD capable of delivering a therapy to a patient-driver and further capable of transmitting an event signal; a telemetry communication module capable of receiving the event signal; a vehicle having an engine, a brake system, an ignition system, a warning system, a communication module and a GPS module; a vehicle control system operable to manipulate one or more vehicle subsystems and generate a status signal based thereon; and a device receiver associated with the IMD for receiving the status signal from the vehicle control system.
Other embodiments include one or more of the following features: providing an implantable medical device in a patient driver; monitoring a hemodynamic parameter such as blood pressure; providing a vehicle control module associated with a telemetry communication module; sensing a medical event with the implantable medical device; generating an event signal with the implantable medical device; transmitting the event signal to the telemetry control module; interrogating the status of the vehicle; manipulating the status of the vehicle; activating a warning indicator; commanding the ignition system to slow or stop the vehicle engine; commanding the brake system to slow or stop the vehicle; generating a status signal with the vehicle control module; transmitting the status signal from the telemetry control module to the implantable medical device; delivering therapy to the patient-driver with the implantable medical device; automatically notifying emergency personnel of the medical event; transmitting the vehicle location to emergency personnel; and activating external emergency signals on the vehicle.
The above summary of the invention is not intended to describe each embodiment or every implementation of the present invention. Rather, a more complete understanding of the invention will become apparent and appreciated by reference to the following detailed description and claims in view of the accompanying drawings.